EVEN in the middle of August, Tremblay Sound in the Canadian Arctic is an inhospitable place. As the small plane descends, I get my first glimpse of our destination. Remote and desolate, it consists mostly of piles of rocks and a little scrubby vegetation. During my two-week stay it will be cold, wet and windy almost all the time. Nobody comes to Baffin Island to get a tan.

Nevertheless, this is the third summer running that Jack Orr from Fisheries and Oceans Canada has visited and, together with a team of scientists, vets and Inuit hunters, he seems right at home. In no time at all they have transformed the site into a fully operational research station, complete with colourful sleeping tents, a kitchen tent and a science lab housed in a plywood shack. Finally, they set their trap. Having firmly anchored one end of a heavy-duty fishing net to the shore, Orr jumps in a boat and crosses the narrow inlet so he can sink the other end to the seabed with a bag of rocks. Six buoys keep the upper edge of the net afloat to create a hanging curtain. All we can do now is await our quarry. Its scientific name is Monodon monoceros, which derives from the Greek for “one tooth, one horn” in reference to the males’ spiralled tusk, which can extend up to 3 metres. Many people simply know these creatures as sea unicorns.

There are some 90,000 narwhals in the frozen northern seas. A small population lives off …